There is a known system for detecting an obstacle around a vehicle, a preceding vehicle, or the like by means of radars. There is also another known system for detecting an obstacle or the like by a combination of a radar with an image recognition unit. These systems for recognizing an obstacle by the combination of the radar with the image recognition unit or by the combination of radars need to perform a process of determining the identity of objects on the occasion of fusion of detection results in the respective detecting devices.
The technology described in Japanese Patent Application Laid-open No. 2003-168197 (Patent Document 1) concerns the fusion of detection results in the system for detecting an object by the radar and the image recognition unit, and the system is arranged to make a decision of “being an identical object” when distances to a detected object, relative velocities, and directions by the radar and the image recognition unit are determined to be equal.